Bird-inspired drones may be able to perch on power lines to recharge

Bird-inspired drones may be ab...
In this lab setup, the glider is able to locate and perch in front of a power line
In this lab setup, the glider is able to locate and perch in front of a power line
View 2 Images
In this lab setup, the glider is able to locate and perch in front of a power line
In this lab setup, the glider is able to locate and perch in front of a power line
The glider incorporates a single servo motor, to control the elevator on the tail
The glider incorporates a single servo motor, to control the elevator on the tail

Unmanned aerial vehicles (UAVs) are currently being considered for many applications, although one factor that a lot of people tend to gloss over is the aircrafts' limited battery range – being able to stay airborne for only 10 to 30 minutes at a time definitely limits their usefulness. Researchers at MIT, however, are developing a possible solution. They're working on a fixed-wing UAV that can perch on power lines and use their emitted magnetic fields to recharge its battery, before continuing on its way.

While multi-rotor UAVs are certainly more adept at perching on things, fixed-wing models tend to be faster and more energy-efficient, thus making them better-suited to a variety of scenarios. The main challenge lies in finding a way of allowing them to halt their forward momentum, stall out, and hook onto a power line.

The MIT team studied birds such as pigeons and eagles in order to find the answer.

They noted how the birds flare their wings and tail, adjust the orientation of their body to a high angle of attack, and assess the trajectory needed in order to perch. These factors and others were used to create a computer model that would allow fixed-wing UAVs to do the same things, using only their own on-board sensors and other electronics for guidance.

The glider incorporates a single servo motor, to control the elevator on the tail
The glider incorporates a single servo motor, to control the elevator on the tail

As a result, the team has so far developed a foam-bodied miniature glider that is consistently able to hook onto a string adjacent to a power line, when launched toward it in a lab. The UAV is even able to locate the power line by detecting the magnetic fields coming from it, and can compensate for light winds when doing so.

In previous experiments at MIT, UAVs were assisted by a series of wall-mounted cameras and a separate computer, that relayed commands to the aircraft.

Perching fixed-wing UAVs (although not ones that use power lines to recharge) are also being developed by the University of Illinois, EPFL, UC San Diego and AeroVironment.

More information on the MIT UAV is available in the video below.

Source: MIT via IEEE Spectrum

Perching with a Simple Fixed-Wing Glider

Bob Flint
Though the idea of induction charging has merit, I think you may need to look at perching somewhat from a different perspective. It seems that the stall angles and landing are starting to work, but how did you plan on releasing and continuing flight? Perhaps a timed hook, that retracts upon full charge, but if the plane is hanging tail down. What happens when it's released? Death spiral? Hanging from near the end of the tail, and now it's facing straight down, possibly able to recuperate if distance is enough, otherwise another death spiral.
How about fly in parallel up to the underside of the cable. With a spring loaded V on the top of the plane, once it hooks, plane hangs for the recharge time, Once it's done hooks release, it drops a few feet, and starts to fly off once again.
Think of the inflight refuelling possibly it does not even need to touch the cables simply follow along close enough to feed of the electromagnetic flow from trailing wires above the power lines?
Ha!!!!....finally...what Tesla has said all along.......about feeding off the electro-magnetics for power....
Now imagine....using the same principle for homes.....
Anyway good idea.
Mel Tisdale
The darn things will be migrating before we know it.
@ Bob Flint
I, too, was thinking that hanging might be more practicable than perching, but mainly because it would be easier to engage a hook from underneath the wire than something to make the UAV sit on top of it.
What is shown may somehow work for single strand power lines but what happens when there are multiple strand power lines. The electromagentic field will be broadcast much wider and how does the drone figure out where each strand is and not foul on the other strands.
@ASHDIL You mean "perching homes" ? 8^)
The power lines in my area use the top wire as a ground and the lower wire would be the likely target depending on the strength of the magnetic fields. Wouldn't it be easier to have the plane fly under the line with a hook on top. A hook attached to a controlled line feed to brake the forward momentum and then pull the plane back up closer to the line. If the hook could rotate with the plane hanging beneath it, the plane could always turn into the wind. When the plane is ready to take off, have it release the hook and start the motor. A light weight plane should only take a few feet of drop before regaining flight speed. The biggest problem with any such system would be the velocity of the wind and surrounding obstacles. High or gusty winds could make the system unusable. Having the propeller stop and fold just before landing would also help prevent it from hitting the power line. I think my idea would work better than what is described in this article. Now if I could just get my hands on some MIT research money.
I didn't see "perching", as abird might. It looked like it was stalling and catching the wire on a hook under the nose. This seems perfectly workable. To detach, just rev up the propellor and the drone lifts off the wire, maneuvers into clear space where it can gain forward momentum and aerodynamic lift so it can fly away. It's common to see RC planes hover pointed vertical, supported by the thrust of their single propellor. At air shows, you can even see piloted stunt biplanes do this trick.
Hi warren52nz, No Friend, I mean feeding off the magnetic field from power lines to power lights, etc. in one's home. ... wirelessly..I am not an electrical engineer but have come across this in literature. The Magnetic field around these power lines can be converted to electricity and transmitted wirelessly. I've seen a guy light up a florescent tube under a pylon without connecting to the pylon itself!!!!....I submit this may only be possible by close proximity but a thought nonetheless. Cheers